The new approach could lead to intranasal vaccines for COVID-19 and other respiratory diseases. RNA vaccines against COVID-19 have proven effective at reducing the severity of disease. However, a team of scientists at MIT is working on making them even better. By tweaking the design of the vaccin
By adding synergistic self-adjuvanting properties to COVID-19 RNA vaccines, MIT researchers have found a new approach that could lead to intranasal vaccines for Covid-19 and other respiratory diseases. Credit: Jose-Luis Olivares, MIT with figures from iStockRNA
The researchers believe that the effectiveness of other types of RNA vaccines that are now in development, including vaccines for cancer, could be improved by incorporating similar immune-stimulating properties. “With the promise of mRNA technologies being realized with the Covid vaccines, we thought that this would be a fantastic opportunity to see if C3d might also be able to play a role as an adjuvant in mRNA vaccine systems,” Jiang says.
To identify lipids that would work best, the researchers created a library of 480 lipid nanoparticles with different types of chemistries. All of these are “ionizable” lipids, which become positively charged when they enter acidic environments. The original Covid RNA vaccines also included some ionizable lipids because they help the nanoparticles to self-assemble with RNA and they help target cells to take up the vaccine.
When the researchers delivered the vaccine intranasally, they observed a similarly strong immune response in the mice. If developed for use in people, an intranasal vaccine could potentially offer enhanced protection against infection because it would generate an immune response within the mucosal tissues that line the nasal passages and lungs.